Phosphate rock beneficiation process



United States atent O PHOSPHATE RGCK BENEFICIATION PROCESS Louis T.Morison, Puentc, and Roy W. Wagoner, Alhambra, Calif., assignors toPetrolite Corporation, Los Angeles, Calif., a corporation of Delaware NoDrawing. Application September 11, 1956 Serial No. 609,054

13 Claims. (Cl. 299-166) This application is a continuation-in-part ofour pending application, Serial No. 598,233, filed July 17, 1956, nowabandoned.

This invention relates to a process for the beneflciation of phosphaterock, for the purpose of removing siliceous impurities therefrom. Theproblem is an important one.

Some million tons of phosphate rock are produced annually from theFlorida pebble phosphate deposits. Located principally in Poll: andHillsborough Counties, these marine deposits produce three-fourths ofthe U. S. supply of phosphate and about three-eighths of the Worldsupply. roduction is approximately 5 times as great as in 1940; andproductive capacity is now being greatly expanded by the companies inthe industry.

Such pebble phosphate, as mined by the conventional strip-miningmethods, includes undesirably large proportions of non-phosphateminerals, principally siliceous and principally silica, which reduce thequality and the price of this large-tonnage, small-unit-value product.Extensive and costly ore'dressing plants have consequently been requiredto be used, todeliver a finished product of acceptable grade.

Among the procedures required to be employed, and one which is almostuniversally used by the industry, is a two-stage or double flotationprocess. In the first stage (or rougher flotation circuit), Washedphosphate rock having particle sizes usually between about 28- and aboutISO-mesh is subjected to the action of a reagent conventionallycomprising tall oil, fuel oil, and caustic soda. The concentratedelivered by such rougher circuit is a phosphate rock of grade higherthan the original rock; but which still contains too much silica andsimilar impurities to be of acceptable market grade.

The rougher concentrate is therefore dc-oiled with dilute sulfuric acid,to remove the tall-oil-soap-and-fueloil reagent; and is thereaftersubjected to flotation in a secondary or cleaner circuit. The frothproduct delivered from this secondary circuit is high in silica andsimilar impurities; and is desirably low in phosphate values, because itis thereafter discarded.

The process of this invention relates to such secondany or cleanerflotation circuit of such conventional flotation scheme, not to suchrougher circuit. (Our process may of course be applied to beneficiate aphosphate rock that has not been subjected to such preliminaryroughercircuit flotation process.)

The conventional cleaner-circuit flotation reagent or collector of theindustry has been a long-chain aliphatic amine acetate. The reagent is apaste, as supplied. The paste is required to be dissolved in hot water,to prepare a dilute solution which can be fed to the cells. Suchhandling procedure is obviously burdensome, and desirably to be avoided,as by use of a liquid reagent dispersible in cold water.

The search for such a liquid, easily-handled reagent has been pursuedfor years; but the standardsilica collector of the phosphate rockindustry is still aliphatic amine acetate. In recent years it has beenfound possible 2,839,191 Patented June 17, 1958 to extend such standardreagent by including a proportion of rosin amine acetate; and,sometimes, also some free or unneutralized rosin amine. Such extenderreagents are not sufliciently effective to be used alone, instead ofaliphatic amine acetate; but since their cost is lower and since theyare compatible with the aliphatic amine acetate reagent, they have foundsome use.

The unneutralized aliphatic amines are in some instances liquids; butthey been have found to possess highly undesirable characteristics asregards skin irritation. Use of such free amines has therefore notoffered a solution of the problem of handling or avoiding the use ofsolid reagents.

One characteristic that a silica collector should desirably possess ifit is to be valuable in the present instance is a tolerance for slimes.Phosphate rock as mined includes particles of all sizes. Hydraulicsizing and other preparatory operations are employed in order to deliverto the flotation plant a feed having a particle size rang ing from about2- to about -mesh. Particles smaller than about ISO-mesh are classed asslimes in the industry. However, even though all slimes originallypresent, both clay and very small phosphate rock particles, are washedfrom the flotation cell feed, the phosphate rock is sufficiently soft toproduce more slimes by the attrition incident to handling and flotation.It is therefore impossible to have a flotation cell feed entirely freefrom slimes.

Slimes consume an inordinate amount of flotation reagent because oftheir relatively vast surface area per unit of weight, and possibly alsobecause of surface forces present on them. The conventional aliphaticamine acetate reagents .are not as slime-resistant or slimetolerant asdesired.

The conventional aliphatic amine acetate reagents, customarily used in adilute aqueous dispersion as just noted, are used at pH level of about 7and higher. To maintain such pH levels, it is conventional practice tofeed caustic soda solution into the cell, along with the amino reagent.Consumption of caustic soda conventionally amounts to as much as 1lb./ton of feed rock; and its use is a significant cost item.

The conventionally-operated secondary or cleaner flotation circuitincludes the use of kerosine. This liquid is fed at rates sufiicient toproduce froths of optimum characteristics. If too much or too littlekerosine is fed, the froth changes appearance in a manner and to adegree which, although diflicult to describe, is nonetheless readilyappreciated by a skilled operator, who knows that, under such conditionsof poor froth appearance, the volume and quality of froth product willbe respectively low and poor. Naturally, from an economic standpoint,

size variations within the about 28-150 range of particle size.

A collector should desirably operate with equal effectiveness on feedsof diflerent grade. While it is naturally desirable to operate a mill onfeed rock of constant composition, this is nearly impossible. Feed mustbe accepted as mined; and variations in the deposit make for larger orsmaller proportions of impurities, different particle sizes, and othervariations in the composition of the feed.

A collector should be selective in its action. Since the fthem in animportant degree, r

. 3 froth product, as delivered from the secondary flotation circuit,isidischarged from the plant, any phosphatevalues it contains arepermanently .lost.' The less selective the f collector used in thatcircuit, the higher the phosphate content of the froth product, and thehigher the phosphate recovery losses' from the plant. Under suchconditions, is said to be low or poor.

An .eflicient collector, used su'iiicient proportions,

is capableof removing substantially all the tree, grains of siliceousimpurities from the phosphate rock. 'The purified rock is conventionallysold on a basis of BPL (bone phosphate of lime) content; and 72% BPL is,a

standard minimum acceptable figure. If the processed rock contains muchsilica or other impurities its 'BPL.

content drops below 72%, with consequent penalties. (Even'wh en' aflotation process is conducted in such fashion as to show substantiallyno free silica grains .in the recovered phosphate rock, under themicroscope, such recovered rock may'still analyze l.O1.5% insolubles.This is due to the fact that some of the insoluble matter 7 simplyfilling a tank part-full of solution water, starting is occluded withingrains of phosphate rock; not being 7 free, it cannot be floated by thesilica collector.) Some collectors will remove the bulk of the insolublematter economically; butare unable to clean the rock of the last severalpercent of insolubles without consumption of large proportions ofreagent.

.This last' statement leads to consideration of another importantfactor. Some "collectors are of such character that their performancedoes not change markedly and quickly with the amount of reagent fed. Forexample,

in some instances,a considerable proportion of reagent must be fedbefore there is evidence of substantial collection or insolubles. Then,one can feed the reagent at a considerably increased rate withoutimproving this first levelof performance. Finally, as-stated just above,one

maybe unable to remove the last traces of insolubles, regardless of theproportion of reagent that is fed. Prompt responseof the operation tochanges in reagent feed rate-or, to express itanother ,way sensitivityof the reagent to changes in the amounts usedis animportantcharacteristic of a desirable collector. V

Dispersibility of the collecting reagent in the system is an extremelyimportant characteristic, and an equally difficult 'one tocatalogf Ifthe reagent is not sufficiently; dispersible inthepulp in the flotationcell, it is present-in relatively large aggregates, or globulesorparticles. One

such particle of, reagent can float only one particle of silica or otherimpurity, even though the lifting of that particle could have beenachieved using'only a fraction of the particle of reagent.

to'concentrate at the rock -air-liquid interface;

Dispersibility may be controlled in a number of ways.

First, the inherent dispersibility characteristics of the 'indi-f vidualreagents will vary. Second, the degree of neutrali-.

Zation of the reagents with'ani acid, such as acetic acid, will usuallyaffect their dispersibility. Finally, the conventional silica flotationplant, in the phosphate industry includes acaustic soda supply system;and caustic soda is conventionally fed at required proportions, tomaintain the most desirable level of reagent dispersion in the secondarycircuit. Conventional aliphatic amine acetate soda feed. ,7 V V V Theforegoing dozen desirable characteristics of a silica reagentsconventionally require the use of such'caustic collector .in thebeneficiatioh of phosphate rock have'be'e'n recited for the reason thattheclass of reagents we have such use possesses.

discovered to be highly effective 'fo'r first, our reagents are liquid}They may'be trans-i ported in conventional steel drums and removedtherefrom by simply removing one of the bungs; They flow readily at alltemperatures to. which they may be'subjected ihi transportation and use,inithephosp'hate rock application.

On the contrary, if a reagent is too dispersible in the pulp, it mayhaverelatively "weak' collecting power, because it has relatively lesstendency They maybe made into diluteaqueous'disp'ersions by Whereas theconventional aliphatic amine acetates rapidly lose the abilitytofloat'silica in the presence of slimes, our present class of reagentsappears to have a high slime tolerance, in that they continue to floatsilica under such conditions.

rises to several hundred parts per million, in the. case of theconventional reagents; but the curve remains quite flat, with ourreagents, at even greater slime concentra tions. V e

Fourth, our reagents are highly effective at the natural pH of theflotation circuit, and without addition ofcaustic soda to produce pHlevels higher than about 7. 'We have found that the cell withoutadditional caustic soda usually has a pH of just under 7. At any rate,irrespective of .the exact pH value, our" reagents appear to' be notcritically sensitive to somevan'ations in pH in the region of ordinaryoperation.

Fifth, while our reagents are advantageously used in conjunction withkerosinc, it appears *that the volume of such liquid required to be usedwith our reagents is somewhat lower than it is when the conventionalaliphatic amine reagents are used. We do not beiieve that use ofkerosine can be entirely dispensed with, however. ,The' reason for thesmaller consumption of kerosinewhen our reagents are used is consideredlater herein. a

content; V v

E1ghth, our reagents appear to have improved seleclarge and smallparticles of siliceous impurities. .random feed'particle sizes'cominginto the plant, our reagents have consistently producedconcentrateshaving Sixth, our reagents appear to be equally. effectiveon With low percentages of insoluble matter. This adaptability todifferent particle sizes is' an obviously important characteristic of acollector. Seventh; our reagents appear to be tio-ns in cell feed.

adaptable to variacentrate, shift after shift, with only the usual minoradjustments of reagent feed and kerosine feedthat must he made in'thecase of any reagent. In no case in whichour reagents have been used on'full-scale operations has there been any difiiculty in keeping the planton-stream.

Feed rock having higher percentages-of insolubleshas' been processedalong with other fee-d having appreciably lower insolubles, withoutaffecting the continuity of the; run or the acceptability of theconcentrates recovered."

During one such run, ourreagentproduced high-grade concentrate for days,althoug-hiat times the feed "rock was belngatakenfiorn' a highagradepit'and at other times camefrom a newly-opened lf'o'wgrade :pit andincluded 7 bits of overburden. Evenwhen thefeed rock contained muchoccluded silica, freely visible under the microscope l (as clear spotson the'milky'phosphate grains), thejrecovered concentrate had anacceptably low insolu bles tivity, as comparcd with conventionalreagents,- in that they fioat relatively much of the siliceousimpurities and relatively little phosphate. The betterreagents of'ourclass produce concentrates havingvery low insolubles;

yet therecovery of phosphate (which is a measure of selectivity, whencoupled with low insolubles content in the concentrate) is good. i

v In other words, the figure for percentage of insolubles in thecencentrate rises steeplyas slime content Full-scale plant runs.haveshown that thefreagent will continueto'recover high-grade con-.

Ninth, our class of reagents is capable of producing concentrates withvery low insolubles contents. During an extended plant run of one suchreagent it was difficult to locate more than one grain of silica perfield, when the concentrate was examined under a low-power microscope;and reagent consumption at the time was below normal for that plant.

Tenth, the insolubles content of the recovered concentrate quicklyreflected changes in reagent feed rate, during the plant run abovementioned. Whenever a grab sample of concentrate showed a slightincrease in siiica content, the reagent feed rate was increasedslightly; and a grab sample taken minutes later showed that asatisfactorily low level of insolubles had been restored.

Eleventh, our reagents have good dispersibility in water, even coldwater. They have appreciable inherent dispersibility in water in theun-neutralized state; and as explained below, their performance issometimes improved by using them in partial salt form.

The reagents we employ in practising our process cornprise a mixture ofa petroleum distillate, particularly a high-boiling aromatic petroleumsolvent, and a co-generic mixture of organic compounds, which may bebest described in terms of its method of manufacture because of thenumber and complexity of its components.

The manufacturing procedure used to produce the cogeneric mixtureinvolves several separate and distinct steps. We have found that suchsteps must be performed separately and in the sequence recited below, ifreagents of high effectiveness are to be produced.

To prepare our reagents, we first react a polyethylenepolyamine withtall oil, under closely controlled conditions of reactant proportionsand reaction conditions. in a second and separate step, We then subjectthe product, so prepared, to reaction with dichloroethylether. Suchsecond reaction product is mixed with an appreciable proportion of apetroleum distillate, preferably a high-boiling aromatic petroleumsolvent, to produce a homogeneous liquid. This liquid, as such or inpartially neutralized form, is our finished reagent. As will be shownlater, it is extremely important from a performance standpoint that the.finished product include such petroleum material.

The polyethylenepolyamines are Well-known articles of commerce. Theyinclude diethylenetriamine, triethylene- .tetramine,tetraethylenepentamine, and binary and ternary mixtures of these invarious proportions. For example, :an 80/20 mixture of the first two ofthese is offered as :a commercial product. So is a 40/60 mixture of thelast two; an 80/ 12/ 8 mixture of the three; and also a ternary mixtureof the three in approximately equal weight proportions.

These are synthetic products, made by a reaction that produces varyingproportions of these homologs, which are separated from the reactionmass by fractional distillation. Such distillation leaves a stillresidue comprising a mixture of polyethylenepolyarnines. Such stillresidue, which includes minor proportions of the above-recited threepolyamines, also is believed to include the higher polyamines such aspentaethylenehexamine, hexaethyleneheptamine, and the like. Such stillresidue is likewise a useful reactant for preparing our reagents, andmay be so used either alone or admixed with one or more of theindividual polyethylene polyamines mentioned.

We have prepared our reagents from various of the polyamines andmixtures thereof. We prefer to use the tower members of the series ormixtures rich in such lower members. Our preferred reactant of thisclass is a mixture comprising about 80% by weight diethylenetriarnineand 20% triethylenetetramine, although we have also prepared a verydesirable reagent of the present kind using triethylenetetramine andtetraethylenepentamine.

We use tall oil as the second reactant in the production of our firstintermediate reaction product. A mixture of fatty and rosin acids, thisproduct arises in the pulp and paper industry. It is of uniquecomposition, is available in large quantities on the open market, and isinexpensive. Either crude or refined grades of tall oil may be used toproduce our reagents. We prefer to use crude tall oil for economicreasons.

The polyamine and the tall oil must be reacted in carefully controlledproportions if a flotation reagent of desirably high eifectiveness is tobe produced. Others have in the past reacted these two classes ofreactants in either equimolar proportions or using an excess ofpolyamine; but we have found the reagents prepared using suchproportions are definitely inferior to those produced using ourproportions.

We have determined that a clearly superior finished rea ent is obtainedif there is present in this reaction mixture appreciably less than anequimolar proportion of the polyamine reactant. As one reduces the molarproportion, polyamine-to-tall oil, from 1:1 down to 0.9:1 and then to0.8: 1, the effectiveness of the finished reagent obtained from suchintermediate reaction product increases materially. As the proportion isreduced further, the improvement in finished-product quality continues.

While there is no sharp break-point in the effectiveness curve, weprefer to employ a ratio, polyamine-to-tall oil, of from about 0.621 toabout 08:1. The intermediates made using reactant proportions withinthis last-recited range produce finished reagents whose effectiveness isclearly better than others made with ratios much outside this range. Wetherefore limit ourselves herein to reagents made from intermediateswhose reactant ratio lies within this narrow range. Our preferred molalratio, polyamine-to-tall oil, is about 0.63: l.

The polyamine and the tall oil are reacted by heating together, withstirring, at a temperature range of quite narrow limits, as we shallnext explain.

When one reacts tall oil and a polyamine, by heating and stirring, wateris evolved as the temperature of "the reaction mass rises. Evolution ofwater first occurs in the neighborhood of C.; and from one-half totwo-thirds. of all the water that will eventually be evolved has comeover by the time the temperature has reached 200 C- Finished reagentsmade from intermediates prepared by heating these two reactants attemperatures not exceeding. 200 C. have poor effectiveness in ourprocess.

As the temperature of the reaction mass is increased to about 250 C.,more water and a small portion of nonaqueous distillate are evolved.(The 250 C. point is mentioned here because it has been the reactiontemperature specified in numerous descriptions of procedures forpreparing amides from polyamines of the present kind.) Products preparedfrom intermediates made at 250 C. do not have acceptable effectivenessin our process, however.

in fact, to prepare our desired intermediate the reaction temperaturemust be held at between 270 and 300 C. for at least part of the reactionperiod. Usual practice is to mix the reactants and start heating andstirring the reaction mass at atmospheric temperature, or slightlyabove. produces a salt, in a slightly exothermic reaction.) The reactionvessel and contents are then brought to the desired reaction temperatureprudently, and the reaction is continued as long as required, at thattemperature. Prudence in heating is required because appreciable foamingaccompanies the reaction and the liberation of water from such reactionmass.

In commercial steel processing vessels, our desired intermediate can beso produced in about 12 hours, of which about 9-10 hours are consumed inreaching a temperature of 285 -290 C.; and about 23 hours are consumedin completing the reaction at this temperature. Below about 270 (2., thefinal and critical portion of the reaction does not occur. It is notnecessary to raise the temperature much above our preferred range of(Mixing the tall oil and the polyamine limiting, however.

asacgiai 7 about 285 -290 C. to complete the desired reaction in arelatively few'hours, as stated; I t a It is also practicable to preparethis first intermediate reactionproduct byheating the-=tall oilto atemperature somewhat above that at which foaming usually occursin suchreaction. For example, ifthe tall oil-isheated to 200-260 C. and thepolyamine is then introduced in small increments, foaming issubstantially-eliminated and an acceptableintermediate is produced.

'I'na second and separate step of preparing ourfinished flotationreagents, the intermediate reaction product prepared as just describedis subjected to reaction with dichloroethylether; While this secondreaction may be conducted inthe same reaction vesselas was; employed toprepare the above intermediate, and without-removing thati firstreaction mass from the vessel, it must be emphasized that the secondreaction, using dichloroethylreaction temperatures appreciably: higherthan these.

For example, we have started the dichloroethylether 7 reaction at 100 C.as above; butthereafter have raised the reaction mass to 150 C. Again,we have added the dichloroethylether at 150 C. and have thereafterraised the temperature of the reaction mass to,20(i' C; t In each case,the reagent so prepared is effectiveffor the present purpose.

This reaction converts a portion of the organically boundchlorineatomsto. chloride ions. The degree of convers'ion'of chlorine to chloride ionwill importantly influence the characteristics of the finished reagent.We prefer to achieve conversion of atleast 35% of the total chlorine,'as a minimum; and we ordinarily convert from about 40% to about 70%.ofsuch' organically-bound f chlorine atoms to chloride ions.

The amount of "chlorine converted can of course be measured byconventional titration "of the chloride ion produced.

As un-ionized, organically-bound chlorine atoms are i converted intochloride ions, the inherent dispersibility of the product inwater'increases. Water-dispersibility of a basic material can usually beincreased by neutralizing it with a low-molal acid, such as acetic, asis Wellknown in this and other arts. We have coined the term inherentdispersibility to distinguish from the conventionalneutralization-derived dispersibility; it'means the tendency of ourbasic material itself to disperse in water.

Such tendency may be concealed in some instances because of the presencein the molecule of large hydrophobic elements; and two such materialsmay appear to be equally not dispersible in water. However, one may bemuch more readily converted into water-dispersible' form, as byneutralization, because of its relatively greater inherentdispersibility. Conversely, two materials may appear to be equallydispersible in water in, say, con- ..centration. Both may producedispersions which, appear alike; yet one dispersion may be considerablymore stable and comprise smaller, more completely hydrated particles. 7Such inherent dispersibility in water may usually beaugrnented byneutralization of the material with an acid, like acetic acid; but it isnotdestroyed by the addi-" tion' of. dilute alkali to a. dispersion, of,such neutralized product.

Such inhereintdispersibility in water, although diflicult to explain,is. believedbv us toberesponsible in part'for We have prepared ourreagents using.

the improved effectiveness of our reagents, as compared withconventional aliphatic amine acetate reagents:

To achieve, it we have found it necessary to employ an appreciableproportion of dichloroethylether in preparing our reagents. We prefer toemploy at least 0.5 equivalent (0.25 mol) of dichloroethylether forevery 1 equivalent (1 mol) of tall oil used in preparing thefirst'intermediate reaction product above, and not more than about 2equivalents (1 mol) of dichloroethylether per equivalent (mol) of talloil.

The range of proportionsof dichloroethylether which may be used toprepare reagents of acceptable effectiveness in our process cannot bestated with decimal exactness. There is no abrupt change ineffectiveness of the products as the proportion of dichloroethyletherused in their preparation is varied. As a practical matter, We

can state that unless we employ about 0.5 equivalent of'dichloroethylether' for each equivalent of tall oil, and unless we soconductthe reaction that at least about of the total chlorine present isconverted to ch10 ride ion, the resulting product is of inferior qualitywhen used'in our process.

After conducting the foregoing two reactions, separately and in thesequence stated, the final' reaction'ma'ss is mixed with a substantialproportion of a petroleum dish'la. late, preferably a high-boilingvaromatic petroleum'solvent; The reaction mass maybe partiallyneutralized either before or after it is mixed with such petroleumdistillate, The petroleum constituent of our finished reagents is notoptionally added to theiother ingredients, when it is desired to reducetheir viscosity 'or lower the products" cost. On the contrary, itspresence is essential. Its

presence is in part responsible for the high effectiveness.

of our reagents. a r

We believe there is an explanation of this important discovery. When ourreagents are dispersed in water, either in a solution tank prior tointroduction into the flotation cell or else in the cell, the reagentparticle that so disperses includes an appreciable proportion ofpetroleum distillate; and the behavior of the particle isdiflfe'rant,and more favorable to the flotation of siliceous im-' purities; thanitwould have been in absence of the petroleum' distillateconstituent,

At any rate, we requirethat our finished flotation reagent include fromabout 25% to about 75% of petroleum distillate. T here-is no option inthis matter; the fin ished reagent must include such constituent, Nofigure can be given for the optimum proportion of such constituent tobeusedp However, it chooses less than about 25% petroleum, distillateand more than about. 75% of,

' final reaction product, prepared as' above described, .the

favorable effect of the combination becomes so small as to benegligible. If one usesmore than about 75% petroleum distillate and lessthan about-25% of reaction product, dispersibility in water becomespoor; and the effectiveness of the reagent is further reduced because inpart the petroleum distiilatejis acting simply as a diluent.

We prefer thatourfinished flotation reagentsinclude.

about reaction product and about 50% petroleum distillate, Suchproportions of reactionproduct and petroleum distillate shouldpreferably lie 'atleast between 40% and .We greatly prefer that thepetroleum distillate con stituent of our finished reagents be 'aso-called'high-boiiingarornatic petroleum solvent. Such liquidsareavailable from refineries, as well-known articles of commerce;

They have boiling ranges of the order of 400 F. initial to over 600 F.endpoint. specification reciting; their content of sulfonatableconstituents, a value determined by reacting the distillate with 98%sulfuric acid and noting the percentage of the sample that dissolves insuch sulfonating agent- Both. the aromatic and'theunsaturatedconstituents of the pe- 1 'troleum distillate dissolve under suchconditions.

not distinguish between these two classes of constituents We do They areusually sold 'on f in our preferred petroleum distillate, because we donot know their respective proportions in the liquids we have used. We doprefer that the petroleum distillate employed as a constituent of ourfinished flotation reagent contain a major proportion of sulfonatables,i. e., of aromatics and unsaturates, and preferably at least about 75%thereof.

Specifications of two representative high-boiling aromatic petroleumsolvents which we have used in preparing So far we are aware, suchhigh-boiling aromatic petroleum solvents have not been used in thephosphate industry, and particularly not in connection with theflotation of siliceous impurities from phosphate rock. So far as weknow, such liquids have never been proposed for use as diluents with theconventional aliphatic amine acetate reagents. (For that matter, we donot believe even kerosine has been suggested to date as a solvent forsuch conventional reagents; because they are not soluble in kerosine atatmospheric temperatures. Where it has been proposed to preparesolutions of such conventional reagents, alcohols have been suggested.)

It should be clearly understood that our mixture of reaction product andhigh-boiling aromatic petroleum solvent is a homogeneous, single-phasesystem, not a dispersion or emulsion or suspension of one constituent inthe other.

The homogeneous mixture of reaction product and pertoleum distillate,prepared as just described, may be partially neutralized with a suitableacidic neutralizing agent. We have employed acetic acid, although it isequally practicable to use hydroxyacetic acid or other organic acid oflow molecular weight. It is equally practicable to use mineral acidslike sulfuric and hydrochloric acids. Acetic acid appears to producereagents having very desirable physical properties; it is our preferredneutralizing agent. We prefer to use it in 94% concentration, althoughWe have used other concentrations. For example, during one field run, weadded common vinegar acetic acid) to our finished reagent, when itbecame desirable to examine the influence of slight additionalneutralization.

Only sufficient neutralizing agent is used to produce a reagent capableof making a smooth, creamy, stable dilute aqueous dispersion; but not somuch as to neutralize the basic constituents completely or even nearlycompletely. If no neutralizing agent is used, the aqueous dispersions ofthe product may in some cases contain particles sufficiently coarse orlarge so that the collector does not do as good a job, even though thedispersion may appear stable to the eye. If too much neutralizing agentis used, the tendency of the reagent particles to concentrate at therock-air-liquid inetrface is reduced.

The foregoing statement does not imply that the proportion ofneutralizing agent usable is so critical that manufacture and use of thereagent are impracticable. We have found that desirably about 1%2% ofacetic acid (100% basis) may be included in some examples of ourfinished flotation reagent if it is to have greatest effectiveness.

A slight deficiency in degree of neutralization, in such instances whereany neutralization at all is used, is not tion of acetic acid to afactory-finished reagent, during the course of a field run, and as thereagent was being dispersed in water preparatory to feeding it to thecell. As our reagents come into settled use in the industry,installation of acid-feeding systems may be made, by means of whichneutralization of the reagents can be effected as desired, for optimumperformance.

Similarly, slightly excessive neutralization of our reagents is notcritical. As stated above, conventional flotation plants presently feedcaustic soda solutions to the cleaner-circuit cells, along with theconventional flotation reagents. It is a simple matter to use a slightlyover neutralized reagent; and then use a small feed of caustic sodasolution to reduce slightly such degree of neutralization of thereagent.

Some operators, accustomed to using caustic soda to control frothcharacteristics, like to have such additional means available to bringunsatisfactory-looking froths back to the desired state. This is anotherreason why slight over-neutralization of our reagents is not critical,and may in fact sometimes be desirable.

There is another important reason for not reciting a more specificdegree of neutralization. The rock fed to the cleaner circuit is theconcentrate from the rougher flotation circuit, after de-oiling andwashing. De-oiling is accomplished by mixing the rougher concentratewith dilute sulfuric acid. Washing is used to remove any excess sulfuricacid from the de-oiled concentrate. In some cases, however, washing isincomplete; and the feed to the cleaner circuit is more acidic thanusual. In such instances, a sli htly under-neutralized reagent givesbetter performance than a slightly over-neutralized one.

It is a virtue of our reagents that they have good adaptability to suchvariations in pH. They do not lose effectiveness sharply on reduction ofcell pH, as do conventional aliphatic amine reagents.

Where neutralization is used, we prefer to neutralize our reagents afteradmixing the reaction productwith the petroleum distillate. However, itis entirely feasible to effect such neutralization of the reactionproduct and then mix the neutralized reaction product with the petroleumdistillate. Neutralizing the mixture of reaction producvt and petroleumdistillate is usually more practicable, because such mixture has aviscosity lower than that of the reaction product alone; anddistribution of the neutralizing agent is more readily eflfected in suchprocedure.

Although we have emphasized the use of aromatic petroleum solvents inpreparing our reagents, we have also referred to this general class ofconstituent as petroleum distillates. We do not intend, by emphasizingthe one example of the class, to imply that it is the only petroleumdistillate that may be used. For example, we have used kerosine inpreparing our reagents; and have found that a mixture of reactionproduct and kerosine, within the proportion limits previously set out,is a flotation reagent of high efiectiveness, in our process.

One observation made during a full-scale run of our preferred reagentwill illustrate how different from conventional reagents our reagentsare. Prior to our run, the plant had operated using the conventionalaliphatic amine acetate reagents, extended with rosin amine acetate andfree rosin amine. The rakes of the flotation cells were heavily slimedwith a deposit of residues from such fatal. As stated above, we haveadded a minor proporreagents. The solution tank in which an aqueousdispersion of such reagents was prepared, and the steel gauge pole usedto measure the level of the liquid in such solution tank, were similarlyslimed. After our reagent had been in use two days, such accumulationsbegan to slough off the cell rakes; and the solution tank wall and thegauge pole were free of deposits.

We have above described in detail our preferred re ac'tants and theproportions thereof employed to produce our finished flotation reagents.The following examples describe the preparation of a number of ourreagents from that they should limit 'the 'preceding description:

' 30 minutes. The resulting homogeneous liquid is allowedmols ofalkylene oxide are used, per mol of polyamine,

such reactants and by such procedures. 'It is not intended.

Example lt.

We first react 2070 pounds of commercial crude tall oil) with 450.pounds of a mixed polyamine, 80% by weight diethylenetriamine andtriethylenetetramine, in.a steelprocessing.vessel equipped withstirrer',and gas-fired. Themass is brought to a temperature of 285 290 C., intl1e course of about 9.5 hours, care'being taken ,to avoid=foamovers andreaction-is'continued at temperature for 2 .25 hours.

Thistfirst intermediate reaction product isallowed-to coolzto 100C. inthe'vessel,;at which .temperature- 300 15 tocool toatmospherictemperature; after which 98 poundsaof 94% commercial aceticacid are added. The. I whole is stirred for another minutes until theacid. is well distributed and neutralization has been accomplished. 30

The finished reagent,'so prepared, is a very effectivev flotationreagent for removing siliceous impurities fromphosphate rock.

The performance of our collector reagent,$of which the. product: ofExampleil is representative, may: fre- '35 quentlybeimproved byusing itin conjunction with a 'minor proportion of a somewhat relatedcompositionwhich we. have found to act as a depressor for phosphate rock. Theeffect of incorporating such-depressorin -ourfinishedfiotation reagentis to make the reagent'more 40 selective for'siliceous and particularlysilica impurities in phosphate'rock. The ability of the collectorcomponent to float siliceous impurities is seemingly not ad=- verselyaffected .by the presence of minorproportions of j such depressor. a V

The depressor components composition is closelyallied to thecompositionof the collector component of those of our' reagents which include bothcomponents. Boththe-collector and the depressor are made'fronr tall oil.Both are made from any. of the polyamines recited above: Both are madeusing' dichloroethylether'in the second intermediate reaction procedure.Both are eventually mixed with a petroleum.'distillate;'and bothmay be'used in unneutralized or partially neutralized state.

The essential difference between the depressor component class and thecollector component class is that the former is made from anoxyalkylated derivative of i one or more of the foregoing polyamines,rather than 1 from the polyamine itself.

We prefer to.employ ethylene oxide alone, .of the alkyleneioxides, forthis purpose, although propylene oxide'sometimes is valuable. At times,a mixture of propylene oxide and ethylene oxide will give the bestdepressor action;'but whereboth are used we prefer that M the propyleneoxide be reacted first, followed by the ethylene oxide. Butylene oxideis not 'useful'alone; but

is useful in conjunction with ethylene oxide.

We prefer that approximately 1 mol of alkylene oxide be used per molofpolyamine. If more than about 2 the desirable characteristics of thisdepressor component are greatly reduced.. Where-more than one alkyleneoxide is used the molal ratio is for total alkylene oxide.-

to-polyamine and we prefer to use a ratio lessth'an abouf r V V 12 about1 mol total alkylene oxide to 1 mol of polyamine, 'Thefollowing' isanex'a'mple of the preparation'of such depressor component. 1

Examp 'Wefirst react 750 Example. 1: with 295 pounds of ethylene'oxidein the conventional manner, employing .a' reaction temperature of1309-135? C.-' No'catalyst is required, inlight of the natural basicityof thestarting material; Theoxyethylanon reaction is eompleteiin-2j5hours. 1 Byathis reaction l mol of. ethylene oxideis introduced intoeach mol of;

polyamine. l I V Thereafter,- the procedure is essentially that-ofExample 1 above; We react 2070 pounds of tall oil. with:

I 627. pounds of the oxyethylated polyamine-justprepared},

raising the temperature to 285290 C. iuabout 10- 7 hours; and'maintaining it'at thatlevel' for 2.5 hours; 7

Such first intermediate reaction product is cooledin V the' reactionvessel to' C., as before; thenJBOO' pounds of dichloroethyletherlarereacted as before; The reaction rises spontaneously to about C., whereit is maintained for '1 hour. Conversion of chlorine atoms to chloride-ions:is about 45%. i V i l The reaction mass is thereafter mixed withBOO-gallons of high-boiling aromatic-petroleum solvent (solvent B5 0above), andstirred-until'the mixture is homogeneou Thereafter; 100poundsof acetic acid (94%)are added;-" and the mass is stirred anadditional 30 minutes; 7

The finished reagent-so prepared, when mixed in minor 'proportion'with acollector component like that-of' Ex ample 1, improves -theselectivityof thatreag ent in re moving siliceous impurities'from phosphate rock.We have-found it advantageous to 'preparea' mixture of such collectorand depressor components, e1; our preferred finished flotatio nreagerit, simultaneously ina single" manufacturing procedure:illustrates such "procedure."

Example 3 V V i We prepare afiotation reagent'having both collector anddepressor constituents, as follows: We first oxyethylate 35 pounds" of amixed polyamine, having by" v weight diethylenetria'mine' and 20%triethylenetetramine, with l3 pounds of ethylene oxide. v I *gether2229*pounds of crude commercial talfoil; pounds of'the above-polyamine,and 48 pounds "of" the" above oxyethylated' polyamine, using amaximum're:

action temperature of 285290 C. for 2.25 'hours,afterf taking some 10hoursto raise the reaction mass'tothis" We cool- 'theireactio'n C.,andadd 323 pounds'of commercial. 7

temperature from atmospheric. mass'to 100 dichloroethylether. Theexothermic reaction which en-i sues raises the'temperature of the massto about 123 '0 Conversion of chlorine atoms to Ichloride'ionslisfabout" 40%? Thereafter; we mix such final reaction' productwith. 268 gallons of high-boiling aromatic petroleumsol vent (solvent A,above), producing'a homogeneous liquid;

Example 4 V we repeat :Example l above,but substituting-for;someI of thereactants and proportions, as followszj'we-react '1850'pounds of talLoilwith 587 pounds of trietliyl'ene tetram'ine, proceeding as before. We,thereaftfer rea'c with such first intermediate reaction -product800ippund" of dichioro etliyleth'er, as before: ,We'tlien'mix'this'secorid 1 2:1'in.any case. Most desirably, we use not morethanintermediate reactioniproductwith'Zdilifpotiirdeofjhigfir pounds of themixed polyamine of The following example' We then react to 13 boilingaromatic petroleum solvent (solvent A, above), as before. Finally, wepartially neutralize the mass with 110 pounds of 94% acetic acid,before. The finished prodnot is an efiective flotation reagent for thepresent purpose.

Example We first react 2070 pounds of tall oil with 965 pounds ofcommercial tetraethylenepentamine, using the procedure and conditions ofExample 1, above. Thereafter, We cool the reaction mass to 105 C. andintroduce, with stirring, 230 pounds of dichloroethylether. Thetemperature rises to about 130 C., where it is maintained 1 hour. Thefinal reaction mass is dropped into 2000 pounds of high-boiling aromaticpetroleum solvent (solvent A, above); and after cooling to roomtemperature is mixed with 98 pounds of 94% commercial acetic acid. Thefinished product is an ef ective flotation reagent for removingsiliceous impurities from phosphate rock.

Example 6 We prepare a depressor component of the kind described inExample 2 above; but with the following reactants and proportions: Weuse 2070 pounds of tall oil, as before. We use 965 pounds of anoxyethylated triethylenetetramine (prepared as in Example 2, but from978 pounds of triethylenetetramine and 295 pounds of ethylene oxide).These two reactants are reacted as in Example 2, to produce a firstintermediate reaction product. This is next reacted with 230 pounds ofdichloroethylether, as before, maximum temperature produced by theexothermic reaction being about 120 C. Thereafter, we mix the finalreaction product with 3000 pounds of kerosine; and neutralize the masspartially with 110 pounds of 94% acetic acid.

. Example 7 We prepare another example of our depressor component asfollows: We react 447 pounds of tetraethylenepentamine and 105 pounds ofethylene oxide, following the procedure set out in Example 2, above. Wethen react 552 pounds of this oxyalkylated polyarnine with 1290 poundsof tail oil; and thereafter react this last reaction product With 290pounds or" dichloroethylether, using the procedures and conditions ofExample 2, above. (In the reaction with dichloroethylether, about 70% ofthe chlorine is converted to chloride ion.) The final reaction productis mixed With 2800 pounds of high-boiling aromatic petroleum solvent;after which the homogeneous liquid is partially neutralized, using 63pounds of 94% acetic acid.

Example 8 We prepare a flotation reagent having both collector anddepressor constituents, by adding, to 900 pounds of the product ofExample 1, 100 pounds of the product of Example 2, above, and stirringuntil thoroughly mixed. The mixture is homogeneous and is an effectivecollector for removing siliceous impurities from phosphate rock. It hasa high degree of selectivity for such impurities.

Example 9 We prepare a flotation reagent having both collector anddepressor components, by adding, to 870 pounds of the product of Example4, above, 130 pounds of the product of Example 6 above, and stirringthoroughly. The homogeneous mixture is an effective collector forremoving siliceous impurities from phosphate rock; and has a high degreeof selectivity for such impurities.

Example 10 We prepare a flotation reagent having both collector anddepressor components as follows: We react 8321 pounds of commercialcrude tall oil with 2536 pounds of commercial triethylenetetramine for2.25 hours at a temperature of 285290 C., after taking about 10 hours toraise the temperature to this level. The product is cooled to C.; and1216 pounds of dichloroethylether are added, with stirring. The reactionmass temperature rises to about C. (About 60% 0f the chlorine present isconverted to chlorine ions.) Then, 7425 pounds of this secondintermediate reaction product are dumped into 8112 pounds of ahigh-boiling aromatic petroleum solvent (solvent A, above); and themixture is stirred for 45 minutes. Thereafter, pounds of 94% commercialacetic acid are added at atmospheric temperature; and the mass isstirred for another hour. Then, 15,697 pounds of this finished productare mixed with 1429 pounds of the product of Example 7, above. Thehomogeneous liquid so prepared is a very etfective collector forremoving siliceous impurities from phosphate rock; and it exhibits ahigh degree of selectivity for such impurities.

Example 11 Example 1 is repeated exactly, except that, instead ofneutralizing with 98 pounds of 94% commercial acetic acid, we neutralizewith pounds of commercial muriatic acid. The product is an effectivecollector for removing siliceous impurities from phosphate rock.

Example 12 We prepare a depressor component of the kind described inExample 2. Example 2 is repeated; but instead of introducing 1 mol ofethylene oxide into the polyamine as a first step, we react 750 poundsof the polyamine first with pounds of propylene oxide and then with 148pounds of ethylene oxide, conditions being substantially the same as inExample 2. Thereafter, we follow the procedure of Example 2 to the endthereof, but using 656 pounds of the present oxyalkylated polyamineinstead of 627 pounds of the derivative of Ex ample 2. 1

Example 13 Example 14 We prepare another example of a depressorcomponent as follows: Example 2 is repeated except that, instead offirst reacting 750 pounds of the 80/20 mixture ofdiethylenetriamine/triethylenetetramine with 295 pounds of ethyleneoxide, We use 590 pounds of this alkylene oxide. The oxyalkylationreaction time is approximately 5 hours. The oxyalkylated polyamine isthereafter used in the procedure of Example 2, employing 804 pounds ofthe present oxyalkylated derivative instead of 627 pounds of thederivative used in Example 2.

Example 15 We repeat Example 1 exactly; but instead of using 2000 poundsof high-boiling aromatic petroleum solvent we use only 840 pounds ofsuch solvent. The product is an effective collector for removingsiliceous impurities from phosphate rock.

Example 1 6 We repeat Example 1 exactly; but instead of using 2000pounds of high-boiling aromatic petroleum solvent we use 7500 pounds ofsuch solvent. The product is an eifective collector for removingsiliceous impurities from phosphate rock.

Example 17 We repeat Example 1 above, except that we use, instead of 450pounds of an 80/20 mixture of diethylenetriamine/triethylenetetramine,930 pounds of a still residue from the manufacture ofpolyethylenepolyamines.

l A typical Florida pebbl This is available from at le'as't onemanufacturer, under thedesignation' Residue H. Thefirstreactiondescribed under Example 1' isthen' conducted as there described, exceptthat heat-up time is extended to some 12 hours. 'The other conditionsandreactantproportions are substantially as stated in Exarnple' l. Theproduct is an effective flotation'reagent for removing siliceousimpurities from phosphaterock.

' 7 Example 18 We react 2455. pounds of crude tall oil', 492 pounds ofmixed polyamine (80% by weight diethylenetriamine, 20%triethylenetetramine), and 53 pounds of the monooxyethylated polyamineof' Example 2, using the procedureof Example 3, above. The firstintermediate reaction. product, 2705 pounds, is next reacted with 367pounds of commercial dichloroethylether, using-a startingreactiontemperature of 100 C. and-prudently raisingthe temperature to 150 C. Thelatter temperature is maintained for 1 hour. Thereafter, 72 poundsofsuchsecond. reaction product are mixed with 2365 pounds of ties fromphosphate rock; and has good selectivitylrwhen so used.

' Example '19 r We react 2291 pounds ofc'rude tallroil, 459 -poundsofthe 'rnixedpolyamine of Example 18, and 50 poundsof the oxyallrylatedpolyamine of Example Reaction conditionsare as recited in Example 3,above To 2 5 24 pounds of this first intermediate reaction product,we=add 253 pounds of dichloroethylether: at 150 C.,-iaddingthe latterreactant slowly.- Thereafter, w'e' raise the' re action mass to 200 C.,and maintain that temperature for 0.5 hour. After cooling,.theifsecondreactionproduct is mixed with 2153 pounds of aromaticpetroleum solvent "(solvent 'A, abbve); and 101 pounds' of 94 .aceticacid are then added, with stirring. 'The finished reagent, so prepared,is an eflectiveflotaitionreagent-for removing siliceous impurities frorrrpl iosphaterock;v an

exhibits good selectivity whensoused. 1 1 3 Example 'j V V We repeateach of the foregoing; exampleg'Examples 1-19 inclusive; but we omit theneutralizationstep and employ the reagent in unneutralized form. Thefinished reagent, so; prepared, are effective flotation reagents forremoving siliceous impurities from phosphate rock; and they exhibit goodselectiw'ty when "so used, especially 7 in-those casesfwhe're adepressorcomponent is included 7 infthe reagent.

Of all the foregoing examples,'we consider the product about /t; belowconventional reagent cost.

of Example 3ftorepresent our preferred reagent. .As-a

second choice, we'p'refer. the product of Example 10. .As'. a'thirdpreferred example of our reagents, we name the reagent. of Example-3;but in'unneutr'alized. form.

Because our'finished'reagents are mosti advantageously usedinconventional flotation plants in the phosphate continued in normalfashion, the only change being .11 9

otherwise used.

Forisake completeness; the' following .brief jexample I of their useisrpresented, without limiting-the'invention:

in any degree; i p r 1 V V e phosphate rock was subjectedto'conventionalpraflotationueatment and sizing; That portion ha vina'particle-size range'of from about 28 to; about l-rnesh was processedthrough a conventional r rougher flotation circuit employing theconventional tall oil, fuel oil, and caustic soda reagents to float aphosphate rock concentrate. The concentrate delivered from'such roughercircuit contained 12l4% insoluble matter, after" de-oiling with dilutesulfuric acidandwashing with'water;

In the consequent secondary flotation circuit, our preferred reagent, asproduced in Example 3 above, was used at a rate of about 0.85 pound perton of rougher concentrate.

Our preferred reagent was dispersed in well Water atrequired for optimumperformance was found to be less than normal. Caustic soda, althoughconventionally fed to the circuit, was'discontinued for optimumperformance of our reagent. After running the plant on feed stocks fromseveral pits over a period of 3 days,

the performance of the plant'while using our preferred" reagent wascompared with the performance during the preceding period whenconventional aliphaticamine' acetate reagent, extended with rosin amineacetate androsin amine, was in use.

Our preferred reagent delivered a concentrate analyzing about.l.5%higher in BPL (bone phosphate of lime), and about 2% lowerin-in'solubles;

The froth product obtained with our reagent analyzed 9% lower in BPLthan did the froth product produced by theconventional reagents. BPLrecovery wasabout 3% higher using our reagent, on an overall'basis. Theplant was operated at higher tonnage rates .duringour run; but-reagentcosts per ton, were nevertheless reduced Elimination of the caustic sodafeed produced another saving of some 3 cents per ton. A smaller(uncalculated) saving was effected by the reduction in kero sin'e feedrate'.' In another application of ourreagents, the product was made inthe plant of a different producer, the conditions, proportions, andresults were'essentially the same as those. described above, except thata 'smallfeed ofQ 'pine oilwas included in the operating procedure. 7, Asin such other application, no diificulty whatever was" experienced inch'anging over from the conventional liquid-j;

reagent to our reagentyand the performance of-"our reagent wastechnologically satisfactory.

As a third example of the application of ourprocess; the reagent ofExample '1 is used and is eflective in a system of the kinddescribedjust above. In such third example, the reagent ofExarnple l'is used inthe'same proportions, and underthe same conditions, as in;.the,. .firstof the above-described fplant procedures. V w r V In, a'fourthoperatingexample, the reagen'tlofEx l ample 3 above is used effectivelyin unneutralized form,"

instead of in partially neutralized form. The first-'de-j scribedoperating procedure above is'emplo'y'ed; The foregoing portion of thisapplication has been devoted to the use of our reagents in conventionalsilica r substitution of our reagents-for the 'conventionalreagentsflotation circuits of phosphate rock beneficiation plants.

'We wish now to state' that ourreagents are likewise" adapted touse' inany of the other conventional con centration processes in'tlie phosphaterock jindustry,'such as in film flotation and tabling, wherein.thefconventionalT aliphatic amine reagents" find 'u tility, In some ofthe appended claims we have therefore claimed 'the'use of' our reagentsin such related'pro ce'sses. The principal applicationof our reagents isbelieved to lie in the froth'flotationprocedure for removingsiliceousiim urities l from phosphate rock, as,conv'ent'iona'lly' operatedthe phosphate fields 'of Florida.

The proportions of. our reagents required w'b'chuseki? Weused gallonsofour reagent to'800 It was pumped to the clean'efv Kerosine was fed tothe cleaner Q circuit in the conventional fashion; but the feedrate willin each case depend upon the composition of the phosphate rock withwhich they are used. However, we believe that our reagents will not beused in proportions greater than those in which the conventionalaliphatic amine reagents are used in this industry. Because our reagentsare generally more effective, pound for pound, such superiority may beexpressed in either of two ways: a smaller feed rate will produce aconcentrate of equal quality; or an equal feed rate will produce a rockof higher quality.

With phosphate rock of sufficiently high grade, our process isapplicable to the washed and sized rock without subjecting such rock tothe action of a rougher flotation operation with tall oil, fuel oil, andcaustic soda, or similar reagents. We therefore do not wish to belimited here to a process in which our reagents are used only on thede-oiled and washed concentrate delivered by such rougher flotationoperation.

In some of the foregoing examples, we have shown the use of an acid andthe partial neutralization of the reagent. It should also be pointed outthat where it is desired to use our reagents in partially neutralizedform, they might equally well be manufactured in the factory withoutusing any neutralizing agent whatever; and any neutralizing acid beadded to the reagent later, e. g., as the latter is introduced into thesolution tank at the flotation plant or to the cells. It is essentialonly, in such cases, that the reagent, as it reaches the flotation cell,be partially neutralized, as described.

We have specified that our depressor component, if present at all, bepresent in only minor amounts. To be more specific, we believe it shouldcomprise not more than about 20% of the total finished reagent. Theexact maximum tolerable proportion will of course depend on theindividual characteristics of the collector and depressor components ofthat particular composition.

In the foregoing specification and in the appended claims we refer tomols of tall oil. It is obvious that, since tall oil is a mixture offatty and rosin acids, it cannot strictly be said to have a molecularweight. However, since the acids of tall oil are monocarboxylic, 1equivalent of tall oil will be the same as 1 mol, total, of the variousacidic constituents of tall oil. Stated another way, if tall oil has anacid number of 173.2, it has an equivalent weight of 324. One equivalentWeight of tall oil is composed of fractional mols of its respectiveconstituent acids, such fractional mols totaling 1.

We claim:

1. A concentration process using differential surface wettabilityprinciples for separating siliceous impurities from phosphate rock,characterized by subjecting the rock to the action of a materialselected from the class consisting of (I) a liquid reagent whichincludes: (A) a reaction product obtained by (1) first reacting tall oiland a polyethylenepolyamine to provide an intermediate, said reactionincluding a reaction temperature between 270 and 300 C., the molalproportion of polyamine to tall oil being between about 0.6:1 and 08:1,then (2) reacting such intermediate with dichloroethylether, the molalproportion of dichloroethylether to tall oil being between about 0.25:1and 1:1; (B) a high-boiling petroleum distillate, the proportion of suchpetroleum distillate in the finished reagent being between about 25% and75%; and a minor proportion of a depressor for phosphate rock, (C) whichdepressor is a reaction product obtained by (1) first reacting tall oiland an oxyalkylated polyethylenepolyamine, said reaction including areaction temperature between 270 and 300 C., the molal proportion ofoxyalkylated polyamine to tall oil being between about 06:1 and 0.8:1,the oxyalkylated polyamine being derived by reacting the polyamine witha material selected from the class consisting of ethylene oxide andpropylene and ethylene oxides, using not more than about 2 mols of totalalkylene oxide for each mol of polyamine; and then reacting such talloil-oxyalkylated polyethylenepolyamine reaction product withdichloroethylether, the molal proportion of dichloroethylether to tailoil being between about 0.25:1 and 1:1; and (II) partial neutralizationproducts thereof.

2. The process of claim 12, in which the concentration process forseparating siliceous impurities from phosphate rock is a froth flotationprocess in which such impurities are floated from such rock.

3. The process of claim 2, in which the petroleum distillate is ahigh-boiling aromatic petroleum solvent, and of which the finishedreagent includes about 40% to 60%.

4. The process of claim 3, in which the high-boiling aromatic petroleumsolvent contains, as a minimum, about of sulfonatable constituents.

5. The process of claim 4 in which the reaction with dichloroethyletherproduces a conversion of chlorine atoms to chloride ions of at leastabout 35%.

6. The process of claim 5 in which the reaction with dichloroethyletherproduces a conversion of chlorine atoms to chloride ions between about40% and 70%.

7. The process of claim 13, in which the oxyalkylated polyamine used toproduce the depressor component is an oxyethylated polyamine in whichthe molal ratio of ethylene oxide residues to polyamine is not greaterthan about 1:1.

8. The process of claim 7, in which the collector and depressorcomponents of the reagent are prepared simultaneously by using a mixtureof polyamines and monooxyethylated polyamines in the reaction.

9. The process of claim 6, in which the polyamine reactant employed toproduce the reagent includes a major proportion of diethylenetriamine.

10. The process of claim 9, in which the reagent is at least partiallyneutralized as manufactured, and before being used.

11. The process of claim 10, in which the neutralizing agent employed isacetic acid.

12. A concentration process using differential surface wettabilityprinciples for separating siliceous impurities from phosphate rock,characterized by subjecting the rock to the action of a materialselected from the class consisting of (I) a liquid reagent whichincludes: (A) a reaction product obtained by (1) first reacting tall oiland a polyethylenepolyamine to provide an intermediate; said reactionincluding a reaction temperature between 270 and 300 C., the molalproportion of polyamine to tall oil being between about 0.621 and 0.8:1,then (2) re acting such intermediate with dichloroethylether, the molalproportion of dichloroethylether to tail oil being between about 0.25:1and 1:1; (B) a high-boiling petroleum distillate, the proportion of suchpetroleum distillate in the finished reagent being between about 25% and75 and (II) partial neutralization products thereof.

13. The process of claim 1 in which the depressor component (C) includedin the finished flotation reagent is not more than about 20% of thefinished reagent.

References Cited in the file of thls patent UNITED STATES PATENTS2,368,968 Christmann Feb. 6, 1945 2,494,132 Jayne Jan. 10, 19502,569,417 Jayne Sept. 25, 1951

1. A CONCENTRATION PROCESS USING DIFFERENTIAL SURFACE WETTABILITYPRINCIPLES FOR SEPARATING SILICEOUS IMPURITIES FROM PHOSPHATE ROCK,CHARACTERIZED BY SUBJECTING THE ROCK TO THE ACTION OF A MATERIALSELECTED FROM THE CLASS CONSISTING OF (1) A LIQUID REAGENT WHICHINCLUDES: (A) A REACTION PRODUCT OBTAINED BY (1) FIRST REACTING TALL OILAND A POLYETHYLENEPOLYAMINE TO PROVIDE AN INTERMEDIATE, SAID REACTIONINCLUDING A REACTION TEMPERATURE BETWEEN 270* AND 300*C., THE MOLALPROPORTION OF POLYAMINE TO TALL OIL BEING BETWEEN ABOUT 0.6:1 AND 0.8:1,THEN (2) REACTING SUCH INTERMEDIATE WITH DICHLOROETHYLETHER, THE MOLALPROPORTION OF DICHLOROETHYLETHER TO TALL OIL BEING BETWEEN ABOUT 0.25:1AND 1:1, (B) A HIGH-BOILING PETROLEUM DISTILLATE, THE PROPORTION OF SUCHPETROLEUM DISTILLATE IN THE FINISHED REAGENT BEING BETWEEN ABOUT 25% AND75%, AND A MINOR PROPORTION OF A DEPRESSOR FOR PHOSPHATE ROCK, (C) WHICHDEPRESSOR IS A REACTION PRODUCT OBTAINED BY (1) FIRST REACTING TALL OILAND AN OXYALKYLATED POLYETHYLENEPOLYAMINE, SAID REACTING INCLUDING AREACTION TEMPERATURE BETWEEN 270* AND 300*C., THE MOLAL PROPORTION OFOXYALKYLATED POLYAMINE TO TALL OIL BEING BETWEEN ABOUT 0.6:1 AND 0.8:1,THE OXYALKYLATED POLYAMINE BEING DERIVED BY REACTING THE POLYAMINE WITHA MATERIAL SELECTED FROM THE CLASS CONSISTING OF ETHYLENE OXIDE ANDPROPYLENE AND ETHYLENE OXIDES, USING NOT MORE THAN ABOUT 2 MOLS OF TOTALALKYLENE OXIDE FOR EACH MOL OF POLYAMINE; AND THEN REACTING SUCH TALLOIL-OXYALKYLATED POLYETHYLENEPOLYAMINE REACTION PRODUCT WITHDICHLOROETHYLETHER, THE MOLAL PROPORTION OF DICHLOROETHYLETHER TO TALLOIL BEING BETWEEN ABOUT 0.25:1 AND 1:1; AND (II) PARTIAL NEUTRALIZATIONPRODUCTS THEREOF.